Facile fabrication and tuning of TiO2 nanoarchitectured morphology using magnetron sputtering and its applications to photocatalysis

Abstract This paper reports a comprehensive investigation into fabrication of TiO 2 nanorods using standard reactive sputtering without applying any further treatment. This approach was considerably different from the typical solution-based process for making TiO 2 nanorods. The key features of this research are that a growth model of TiO 2 nanorods is proposed based on the random distribution of anatase TiO 2 (1 0 1) on a fluorine-doped tin oxide substrate. In addition, three critical factors, the morphology, band gap tuning, and chemical environment, were examined simultaneously to enhance photocatalysis of TiO 2 nanorods. We observed that the morphology can be modulated by varying the sputtering parameters and N 2 doping. Scanning electron microscopy and transmission electron microscopy results indicated a unique large polycrystalline nanorod bundle that was composed of various small highly textured nanorods dominated by the low energy facets of anatase (1 0 1). X-ray photoelectron spectroscopy was performed to confirm that Route B (an Ar (20 mTorr)/N 2 (10 mTorr) atmosphere followed by O 2 postannealing) was an effective approach for doping N 2 into TiO 2 nanorods, in which some Ti 3+ formed (Ti 3 + Ti4+ − ) to maintain charge neutrality in the N 2 -doped TiO 2 (N-TiO 2 ) system, because of the substitutional formation of N 3− O2− − . The sample exhibited higher photocatalytic efficiency than did pristine TiO 2 nanorods. Approximately 80% of methylene blue decomposed in 90 min at a pH of 10 under visible light illumination.